Green tea extract subjected to cation exchange treatment and nanofiltration to improve clarity and color

ABSTRACT

Green tea extracts having improved clarity and color. These extracts are obtained by treating the green tea extract with an amount of a food grade cation exchange resin effective to remove metal cations present in the extract. The treated extract is then contacted nanofiltration membrane while the treated extract is at a temperature of from about 100° to about 140° F. (from about 37.8° to about 60° C.) to provide a filtered green tea extract as the permeate. These green tea extracts can be included in a variety of beverages and are especially useful in suppressing the characteristic aftertaste of aspartame in diet beverages.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation of, U.S. Ser. No. 08/606,907 now U.S.Pat. No. 6,063,428 filed on Feb. 26, 1996.

TECHNICAL FIELD

This application relates to a process for preparing green tea extractshaving improved clarity and color. This application particularly relatesto a process for preparing these green tea extracts involving treatmentwith a cation exchange material, followed by nanofiltration. Thisapplication further relates to beverages prepared with these green teaextracts.

BACKGROUND OF THE INVENTION

The extraction of tea material is well known in the art. For examplegreen tea is typically extracted with hot or cold water to form a diluteextract containing soluble tea solids. This green tea extract can beconcentrated to form a concentrated extract which is sold in frozen,refrigerated or dried form. This green tea extract can also be combinedwith other beverage ingredients such as fruit juice, nectar, etc., toprovide beverages having at least some of the desired flavor and sensorycharacteristics of green tea

Green tea extracts initially contain high levels of unoxidizedflavanols, especially monomeric catechins such as epicatechin,epigallocatechin, epigallocatechingallate and epicatechingallate thatimpart a desired taste quality (astringency) to the tea beverage.Unfortunately, these catechin components (molecular weight of from about200 to about 500) can be oxidized to higher molecular weightpolyphenols, especially the theaflavins and thearubigins, in thepresence of other components in the extract. These other componentsinclude metal ions (especially calcium, magnesium, manganese, aluminum,zinc and iron), certain partially oxidized organic intermediates(especially quinones) that are formed when the green tea is initiallyextracted, and dissolved oxygen. These metal ions in the extract act asa catalyst, and along with the quinones and dissolved oxygen, convertthe catechins to oxidized polyphenols that impart a less desirable,lingering astringency to green tea beverages.

These oxidized polyphenols that are formed by the oxidation of thecatechins can interact and react with other materials in the green teaextract, such as caffeine, protein, pectins and/or metal ions, to formeven larger and heavier complexes that eventually precipitate out. As aresult, the tea beverage turns from the desired pale green color to anunappealing brown color over time. More importantly, the tea beveragebecomes cloudy, turbid and develops a visible precipitate within a fewdays.

This discoloration and precipitation of complexed materials in teacontaining beverages is not visually appealing. Some consumers considersuch beverages to be distasteful and “old”. Moreover, where it isdesired to provide “clear” beverages containing green tea, the fact thatthese green tea extracts can change color and become turbid is certainlyundesirable.

Attempts have been made to remove these complexes from green teaextracts. These methods include changing processing conditions,especially temperature to cause precipitation, followed bycentrifugation, filtration, and removal of the precipitate. Othermethods include suspending and stabilizing the oxidized polyphenols. Seefor example, U.S. Pat. No. 4,051,261 (Jongeling) issued Sep. 27, 1977.Still other methods include using chemical and enzymatic agents tosolubilize the insoluble components, or using solvents to extract thetea leaf, so that only the unoxidized catechins are extracted. Evenafter using these methods, the catechins will still be oxidized overtime to the less desirable oxidized polyphenols. Also, when the greentea extract is incorporated into a beverage having non-tea materialssuch as juice, punch, and/or nectar, the beverage can turn anunappealingly brown color and can become “muddy” with time.

Another method that has been used to lower the level of oxidizedpolyphenols such as the theaflavins and thearubigins, and to increasethe levels of desired catechins, as well as the desired amino acidtheanine, is disclosed in U.S. Pat. No. 5,427,806 (Ekanayake et al),Jun. 26, 1995. In this prior Ekanayake et al process, green tea isextracted with an aqueous acid solution of erythorbic acid and/orascorbic acid, plus citric acid. The acid extracted tea solution is thentreated with gelatin and the resultant precipitate filtered out. Thisprior Ekanayake et al process removes some of the undesired oxidizedmaterials as well as iron that can be present in the green tea extract.However, not all of the undesired components in the green tea extractare removed, including metal ions other than iron (e.g., calcium andmagnesium), the theaflavins, and complexing components such as pectinsand proteins. Accordingly, there is still a need for a process that canprovide a green tea extract in which components contributing to oxidizedpolyphenols and other complexing components are minimized, reduced orremoved so that the resultant extract has improved clarity and colorover time.

DISCLOSURE OF THE INVENTION

The present invention relates to a process for producing a green teaextract having improved clarity and color over time. This processcomprises the steps of:

a. providing a green tea extract that has been optionally, butpreferably, obtained by:

(1) contacting green tea material with an aqueous acid solutioncomprising erythorbic acid, ascorbic acid, or mixtures of erythorbic andascorbic acid, plus citric acid, to provide a first aqueous extractcontaining soluble green tea solids;

(2) separating the first aqueous extract from the residual green teamaterial;

(3) contacting the residual green tea material of step (2) with anaqueous acid solution comprising erythorbic acid, ascorbic acid, ormixtures of erythorbic and ascorbic acid, to provide a second aqueousextract containing soluble green tea solids;

(4) separating the second aqueous extract from the residual green teamaterial; and

(5) combining the first and second aqueous extracts to provide the greentea extract;

b. treating the green tea extract with an amount of a food grade cationexchange material effective to remove metal cations present in theextract;

c. contacting the treated extract with a nanofiltration membrane whilethe treated extract is at a temperature of from about 100° to about 140°F. (from about 37.8° to about 60° C.) to remove higher molecular weightcomponents and to provide a filtered green tea extract as the permeate.

The present invention further relates to the filtered green tea extractobtained by this process. This filtered extract comprises, on a 1%soluble solids basis:

a. a mixture of catechins comprising:

(1) at least about 130 ppm of epicatechins;

(2) at least about 300 ppm of epigallocatechins;

(3) at least about 350 ppm of epigallocatechingallates;

(4) at least about 60 ppm of epicatechingallates;

b. at least about 50 ppm of theanine;

c. optionally, but preferably, at least about 450 ppm of caffeine;

d. about 10 ppm or less each of calcium, magnesium, manganese, aluminum,zinc and iron ions;

e. an absorbance of about 0.06 or less when measured at 600 nm;

f. optionally, but preferably, an absorbance of about 0.6 or less whenmeasured at 430 nm

g. optionally, but preferably, a titratable acidity (TA) of at leastabout 0.1%.

The treatment of the green tea extract with the cation exchange materialimproves clarity by removing metal ions, especially calcium andmagnesium ions, that can bind with pectin or proteins (or pectin-like orprotein-like components) in the extract to form complexed molecules thatcan precipitate out and cause turbidity. Most importantly, thistreatment with the cation exchange material gets rid of these metal ionsas potential catalysts of the oxidation of catechins to oxidizedpolyphenols such as the theaflavins and thearubigins. In addition, wherethe cation exchange material is a strongly acidic cation exchange resin,hydrogen ions are added that minimize or reduce the need for additionalacidity (e.g., adding edible acids) extract so that beverages preparedfrom this extract have a smooth, less tart, astringent taste.

The step of contacting the treated green tea extract with ananofiltration membrane removes the larger, high molecular weightcomponents. These include the pectins, proteins, chlorophylls (andrespective degradation products of chlorophylls), thearubigins and sometheaflavins, and oxidation products due to residual metalions/complexes. The removal of these higher molecular weight componentsimproves the clarity and color of the resultant filtered extract (thepermeate), even over time. The filtered extract is enriched in thedesired catechins that impart desired flavor characteristics to greentea extracts. An additional benefit is that the filtered extract isenriched in theanine, a desirable green tea component that mellows theastringency imparted by the catechins.

The treated, filtered green tea extract resulting from the process ofthe present invention can be used as is to provide desirable green teabeverages. This green tea extract can also be combined with otherbeverage ingredients, including fruit juices, to provide a wide range ofgreen tea-containing beverages. Another surprising benefit of thesegreen tea extracts in diet beverages is that the characteristicaftertaste of aspartame is substantially suppressed.

DETAILED DESCRIPTION OF THE INVENTION

A. Definitions

As used herein, the term “soluble solids” refers to the soluble teasolids extracted from tea that are soluble in water, plus any otherwater-soluble components that are included during extraction orsubsequent processing. These solids can include caffeine, flavanols,amino acids (especially theanine), edible acids (e.g., citric acid,erythrobic acid and ascorbic that added during acidic extraction asdescribed hereafter), and their salts, proteins, sugars and relatedmaterials. All amounts given for the components (e.g., catechins)present in the tea extract or tea solids are based on 1% soluble solids.

As used herein, the term “green tea materials” or “green tea solids”refers to green tea materials or solids obtained from the genus Camelliaincluding C. sinensis and C. assaimica, or their hybrids, for instance,freshly gathered green tea leaves, fresh green tea leaves that are driedimmediately after gathering, fresh green tea leaves that have been heattreated before drying to inactivate any enzymes present, unfermentedtea, instant green tea, and aqueous extracts of these leaves. Green teamaterials are tea leaves, their extracts, tea plant stems and otherplant materials which are related and which have not undergone partialor substantial fermentation to create oolong or black teas. Othermembers of the genus Phyllanthus, Catechu gambir or Uncaria family oftea plants can also be used. Mixtures of unfermented teas can be alsoused in preparing green tea extracts according to the present invention.

As used herein, the term “catechins” refers generally to catechins,epicatechins, and their derivatives. These derivatives include the sugarsalts, sugar esters, and other edible physiologically availablederivatives. Catechins, epicatechins, and their derivatives are the keyflavanols present in green teas. For the purposes of the presentinvention, the level of catechins in the green tea solids, extracts ormaterials is based of the level of four of these flavanols: epicatechin,epigallocatechin, epicatechingallate, and epigallocatechin gallate.However, it should be understood that other catechins can be present ingreen tea, such as gallocatechin and gallocatechin gallate.

As used herein, the term “comprising” means various components andprocessing steps can be conjointly employed in the green tea extracts,products and process of the present invention. Accordingly, the term“comprising” encompasses the more restrictive terms “consistingessentially of” and “consisting of.”

All amounts, parts, ratios and percentages used herein are by weightunless otherwise specified.

B. Starting Green Tea Extract and Pretreatment Step

Green tea extracts useful in the present invention can be obtained fromgreen tea materials or other natural sources of green tea The green teaextract is typically obtained by contacting green tea leaves or othergreen tea materials with water to provide an aqueous extract. In thoseinstances where the source of green tea materials have been carefullyhandled to avoid the initial generation of precursors such as quinonesthat can cause the oxidation of the desired catechins to the lessdesirable higher molecular weight oxidized polyphenols, such as thetheaflavins and thearubigins, the green tea extract obtained can beprocessed according to the present invention without acidic extraction,i.e., extraction with an acidic aqueous solution. However, in mostinstances, it is preferred that the starting green tea extract beobtained by acidic extraction to remove some of the metal ions, such asiron, and some of the oxidized phenolic components such as theaflavins,thearubigins, and quinones.

Acidic extraction is preferably carried out according to the processdescribed in U.S. Pat. No. 5,427,806 (Ekanayake et al), Jun. 26, 1995,which is incorporated by reference. In the Ekanayake et al process, thegreen tea materials are contacted or extracted with an aqueous solutioncontaining citric acid, as well as erythorbic acid, ascorbic acid, or amixture of erythorbic and ascorbic acids. Preferably, the extractionwater to which these acids are added is deionized.

The extraction with this acid solution can be carried out batchwise,semi-continuously, continuously or by equivalent procedures. Thepreferred methods are batchwise or semi-continuous.

In the batch method, the green tea materials are preferably extracted ata temperature of from about 40° to about 50° C., most preferably fromabout 45° to about 50° C., with an aqueous solution containing about ½to about ¾ of the total amount of erythorbic acid/ascorbic acid and thetotal amount of citric acid used in the extraction process. The ratio oftea material to aqueous solution is typically from about 1:7 to about1:20, more preferably from about 1:7 to about 1:9, and most preferablyabout 1:8. The ratio of erythorbic acid/ascorbic acid to tea materialused is typically from about 1:6 to about 1:60, preferably from about1:7 to about 1:50. The ratio of citric acid to tea material is typicallyfrom about 1:10 to about 1:40, and preferably from about 1:20 to about1:35.

The extraction with this acid solution is carried out for a period oftime sufficient to produce an aqueous extract containing typically fromabout 0.75 to about 2.5% soluble solids, preferably from about 1 toabout 2% soluble solids. This aqueous extract is separated from theresidual tea materials and other solid tea residue, for example, bysettling and decanting, filtration, or centrifugation. A second acidsolution containing the remaining erythorbic/ascorbic acid is then addedto the residual tea material/residue at a ratio of typically from about1:7 to about 1:20, and preferably from about 1:8 to about 1:15. Thissecond extraction is carried out at temperature of typically from about40° to about 48° C., and preferably from about 43° to about 46° C. Thesecond extraction is carried out for a period of time sufficient toproduce a second aqueous extract containing typically from about 0.5 toabout 2.0% soluble solids, preferably from about 1.0 to about 1.5%soluble solids. After removing the residual tea material from thissecond aqueous extract, the first and second aqueous extracts are thencombined together to provide the green tea extract for subsequentprocessing according to the present invention.

When using a semi-continuous method, the green tea materials are againextracted with an acid solution containing citric acid and erythorbicacid, ascorbic acid or mixtures of erythorbic acid and ascorbic acid.The first step of this semi-continuous method involves adding from about½ to about ¾ of the total amount of erythorbic acid, ascorbic acid ormixtures thereof to be used in the process and the total amount ofcitric acid to a tank containing water. Since the amount of acids to beadded are based on the weight of tea material, the weight of teamaterial to be added is determined in advance. The ratio of erythorbicand/or ascorbic acid to tea leaves is typically from about 1:6 to about1:60, preferably from about 1:7 to about 1:50; and the ratio of citricacid to tea material is typically from about 1:10 to about 1:40,preferably about 1:35. The tea materials are then added to the aqueoussolution containing the acids. The ratio of aqueous acid solution to teamaterial is typically from about 1:7 to about 1:20. The tea materialsare completely wetted. The extraction is carried out at a temperature oftypically from about 40° to about 50° C., preferably from about 45° toabout 50° C., until the green tea solution reaches a Brix of greaterthan about 4. From about 60 to about 80%, preferably from about 65 toabout 75%, most preferably 70%, of the solution (first portion) ispumped into a filter tank. This first portion of green tea extract ispumped under vacuum to limit the oxygen content of the extract to avacuum tank to provide the green tea extract for subsequent processingaccording to the present invention. Additional water containing theremaining erythorbic/ascorbic acids is used to flush the filter tank.This flush solution is added to the filter tank until the tea extractreaches a Brix of from about 1 to about 3, preferably from about 1.5 toabout 2. The remainder of the green tea solution (second portion) isused to extract another quantity of fresh green tea materials, therebyincreasing the soluble solids level.

The green tea extracts resulting from this acid extraction (aftersubsequent processing and concentration as described hereafter)typically comprise from about 20 to about 60% soluble solids, from about3 to about 17% (preferably from about 2 to about 15% and more preferablyfrom about 3 to about 11%) erythorbic and/or ascorbic acid; from about 1to about 6% (preferably from about 2 to about 5%, and most preferablyfrom about 2.5 to about 3.3%) citric acid; from about 1 to about 25%(preferably from about 6 to about 20%, and most preferably from about 7to about 15%) catechins (i.e., the combined level of epicatechins,epigallocatechins, epigallocatechingallates and epicatechingallates);and from about 0.85 to about 4% caffeine. The theanine to caffeine ratiois typically from about 1:3 to about 1:100, preferably from about 1:4 toabout 1:80. The ratio of theanine to oxidized catechins (e.g.,theaflavins and thearubigins) is typically from about 1:10 to about1:150, preferably from about 1:20.

C. Treatment of Extract with Cation Exchange Material

A key aspect of the present invention is to treat the green tea extract(with or without acidic extraction) with a food grade cation exchangematerial. This treatment with a cation exchange material removes metalions that are the catalysts for oxidation reactions that convert themonomeric catechins to polymeric oxidized polyphenols such as thetheaflavins and thearubigins. Removal of these metal ions, especiallythe calcium and magnesium ions, can also improve clarity by preventingthe metal ions from complexing with other components in the extract,especially the pectin or pectin-like components. It is these complexedmolecules that can cause undesired turbidity.

This treatment is typically carried out by contacting the green teaextract with a food grade cation exchange resin. The ratio of resin toextract is such that the resin is effective at removing the metal ionsin the extract, especially calcium, magnesium, manganese, aluminum, zincand iron. Typically, the ratio of extract to resin is in the range offrom about 1:1 to about 30:1, preferably from about 1:1 to about 15:1.This ratio of extract to resin can also be important in determiningwhether substantial amounts of caffeine that is in the extract areremoved. If there is a huge excess of cation exchange resin (e.g., ratioof extract to resin smaller than about 1:15), substantial levels ofcaffeine can be removed from the extract. For decaffeinated green teaextracts according to the present invention, using such an excess ofcation exchange resin can be desirable. However, for green tea extractsaccording to the present invention that are caffeinated, such an excessof cation exchange resin should be avoided. If desired, the cationexchange resin can be replaced by a cation exchange membrane, i.e.,where the cation exchange material is attached to a support member orsubstrate.

The green tea extract can be treated with the cation exchange resinusing any conventional method that results in the intimate contact ofthe resin and the extract. Suitable methods include fluidized beds,stirred tanks, batch tanks, and concurrent and countercurrent flowcolumns. This treatment step can occur batchwise, semi-batchwise,semi-continuously or continuously. Typically, the green tea extract ispassed continuously through a laterally confined column of the cationexchange resin. When passed through a column or fluidized bed of theresin, the flow of the extract can be either in an upflow or downflowdirection.

A variety of food grade cation exchange resins can be used in treatingthe green tea extract. Particularly preferred cation exchange resins foruse in the present invention are those referred to as “strongly acidiccation exchange resins” that include sulfonated copolymers of styreneand divinylbenzene, sulfite-modified cross-linked phenol-formaldehyderesins that have sulfonic acid groups in the side chains and sulfonatedtetrapolymers of styrene, divinylbenzene, and acrylonitrile or methylacrylate. These strongly acidic cation ion exchange resins add hydrogenions to the extract, and thus reduce the need to add additional acids tothe extract, especially when formulating beverages. Suitable stronglyacidic cation ion exchange resins include those sold under the tradenameAmberlite IR-116, IR-118, IR-120B, XT-1022E, XT47F (all manufactured byOrgano division of Rohm & Haas), Diaion SK-1B, SK-102, SK-104, SK-106,SK-110, SK-112, SK-116, FR-01 (all manufactured by MitsubishiChemicals), and XFS-43281.00, XFS-43280.00, XFS-43279.00, XFS-43278.00,HCR-W2 (all manufactured by Dow Chemicals), and Wofatite-KPS(manufactured by Bayer).

The amount of time the green tea extract is kept in contact with thecation exchange resin (residence time) is largely dependent upon thetype of resin used, the degree of metal ion removal desired, the levelof metal ions initially present in the extract, the amount of resinused, the temperature of the extract, and the pH of the extract. Theprimary factor determining residence time is the degree of metal ionremoval desired. The extract is typically contacted with the cationexchange resin until the level of metal ions (i.e., calcium, magnesium,manganese, aluminum, zinc and iron ions) in the extract is each about 10ppm or less. Preferably, the level of each of these metal ions is about5 ppm or less. The residence time of the extract in a column of thecation exchange resin is usually controlled by the flow rate of theextract through the column. Typically, the extract flows through thecolumn of resin at a rate of from about 1 to about 5 gal./min./ft³.Preferably, the extract flows through the column of resin at a rate offrom about 2 to about 4 gal./min./ft³.

There is no particular criticality in terms of the temperature at whichthis cation exchange treatment is carried out. Suitable temperatures canbe anywhere in the range of from ambient to the temperature at which thesubsequent nanofiltration step is carried. Typically. cation exchangetreatment according to the present invention is carried out atemperature in the range of from about 77° to about 140° F. (from about25° to about 60° C.).

Typically, the pH of the effluent extract initially drops. However, overtime, the cation exchange resin becomes exhausted (i.e. loaded withions). Where strongly acidic cation exchange resins are used, this isusually evidenced by a sharp increase in the pH of the effluent extractabove about 3. At this point, it becomes necessary to restore theexhausted resin back to the point where it is capable of removingadditional amounts of metal ions from the green tea extract. Restorationis achieved by desorbing the metal ions from the cation exchange resin.Desorption of the resin is typically carried out by first washing outthe resin bed with deionized water to ensure that no residual teaextract remains. Then a strong acid such as hydrochloric acid (4 to 10%solution) or sulfuric acid (1 to 8% solution) is fed through the resinbed, typically at a rate of from about 0.15 to about 0.5 gal./min./ft³until the effluent pH is about 1, followed by washing with deionizedwater (typically about 6 bed volumes) until the wash water has a neutralpH. The resin bed is then ready for treatment of the next batch of teaextract.

D. Nanofiltration of Treated Extract

Another key aspect of the present invention is to contact the cationexchange resin treated extract with a nanofiltration membrane to providea filtered green tea extract as the permeate. Nanofiltration accordingto the present invention removes the higher molecular weight materialssuch as the pectins, proteins, chlorophylls (and respective degradationproducts), thearubigins, some theaflavins, and other oxidation productsthat form complexes with any residual metal ions in the extract.

As used herein, “nanofiltration” refers to processes that use filtrationmembranes having a smaller molecular weight or pore size than thosetypically used in ultrafiltration processes, but larger than thosetypically used in reverse osmosis processes. Like ultrafiltration,nanofiltration rejects only a portion of the solute components above acertain molecular size while passing those of a smaller size. Bycontrast, reverse osmosis membranes generally reject all solutecomponents, including ions and will pass only water molecules.

An important aspect of the process of the present invention is that thisnanofiltration step be carried out while the extract is at a temperatureof from about 100° to about 140° F. (from about 37.8° to about 60° C.),preferably from 105° to about 115° F. (from about 40.6° to about 46.1°C.). This is typically achieved by warming the extract after treatmentwith the cation exchange material and just prior to nanofiltration.Carrying out this nanofiltration step while the extract is within thistemperature range is important in two respects. If the temperature ismuch below about 100° F. (37.8° C.), desired amino acids such astheanine can be complexed with oxidized polyphenols to form largermolecules that are then removed by the membrane during nanofiltration ofthe extract. Conversely, if the temperature of the extract is much aboveabout 140° F. (60° C.), some of the complexed oxidized materials in theextract will disassociate to smaller molecules that can then passthrough the membrane during nanofiltration.

The pressure at which nanofiltration is carried out can be important inthe process of the present invention. The pressure at whichnanofiltration is carried out has to be high enough to provide adequateflow of the extract (i.e., permeate) through the membrane to achievedesired processing efficiencies. However, the pressure should not be sohigh that substantial amounts of water are removed from extract, i.e.excessive concentration of the concentrate (i.e., retentate) should beavoided. Typically, nanofiltration according to the present invention iscarried out under a hydrostatic pressure of from about 100 to about 300psi, preferably from about 175 to about 250 psi, applied to the upstreamside of the membrane.

Suitable nanofiltration membranes for use in the process of the presentinvention are made from polymers having a nominal molecular weight cutoff of from about 700 to about 5000 Daltons (corresponding to pore sizesin the range of from about 17 to about 40 Angstroms). Preferrednanofiltration membranes are made from polymers having a nominalmolecular weight cut off of from about 800 to about 2000 Daltons(corresponding to pore sizes in the range of from about 18 to about 27Angstroms). By use of a membrane having the appropriate nominalmolecular weight cut off or pore size, the desired tea components (e.g.,catechins) in the extract of a molecular size smaller than the nominalpore diameter of the membrane, along with a large quantity of water, arethus forced through the membrane and accumulate on the downstream sideas the permeate, while the undesired molecules (e.g., oxidizedpolyphenols such as some of the theaflavins and thearubigins) of amolecular size larger than the nominal pore diameter of the membrane,are rejected by the membrane and remain on the upstream side thereof asthe retentate.

The type of polymers used in making the nanofiltration membrane can alsoimportant in the process of the present invention. Suitable polymerswill be those that have less affinity for the desired components in theextract (e.g., the catechins). Polymers such as cellulose acetates,polysulfones, polyvinylidenefluorides, and the like are usually suitablefor making these nanofiltration membranes. See, for example, U.S. Pat.No. 4,604,204 (Linder et al), issued Aug. 5, 1986, that disclosessuitable cellulose acetate membrane materials. However, polyamide (e.g.,nylon) type polymers are usually unsuitable as membrane materialsbecause the polymer from which the membrane is made has too great anaffinity for the catechins and will thus remove or filter out too muchof these desired components from the green tea extract.

The nanofiltration membrane can be in a number of differentconfigurations and are usually positioned within a cartridge typeassembly or module. Preferred membrane configurations for use in theprocess of the present invention are commonly referred to as “spiralwound membranes.” Spiral wound membranes typically include a centrallypositioned permeate or filtrate tube and at least one sheet of amembrane with appropriate spacer and backing that is spirally woundaround the permeate or filtrate tube. See, for example, U.S. Pat. No.5,470,468 (Colby), issued Nov. 28, 1995; U.S. Pat. No. 5,192,437 (Changet al), issued Mar. 9, 1993; U.S. Pat. No. 4,994,184 (Thalmann et al),issued Feb. 19, 1991; U.S. Pat. No. 4,998,445 (Falk), issued Jan. 29,1991; U.S. Pat. No. 4,781,830 (Olsen), issued Nov. 1, 1988; U.S. Pat.No. 4,301,013 (Setti et al), issued Nov. 17, 1981, that discloserepresentative spiral wound membrane cartridges of the general type thatcan be used in carrying out nanofiltration according to the presentinvention. In the case of spiral wound configurations, the membraneshould not be so tightly wound as to unduly impede the flow rate ofextract around and through the membrane.

Other suitable configurations include tubular arrays of hollow fibermembranes where a plurality of hollow membrane fibers (e.g., 3 to 20)are disposed within a modular housing. See U.S. Pat. No. 4,997,564(Herczeg), issued Mar. 5, 1991; U.S. Pat. No. 4,992,177 (Fulk), issuedFeb. 12, 1991; U.S. Pat. No. 4,959,149 (Raneri et al), issued Sep. 25,1990; U.S. Pat. No. 4,435,289 (Breslau), issued Mar. 6, 1984, thatdisclose modules containing tubular arrays of hollow fiber membranes ofthe general type that can be used in carrying out nanofiltrationaccording to the present invention. Flat sheet filter cartridgescontaining a series of 2 or more spaced apart membrane plates or sheetscan also be used in carrying out nanofiltration according to the presentinvention.

After the extract has been subjected to nanofiltration according to thepresent invention, it is desirable to cool the resulting tea extractpermeate. As noted previously, the extract is typically warmed prior tonanofiltration. However, leaving the resulting extract permeate in thiswarm condition can cause undesired oxidation of the desired and enrichedcomponents (especially catechins) still present in the extract permeate.Typically, the extract permeate is cooled to a temperature of about 60°F. (15.6° C.) or less, preferably about 45° F. (7.2° C.) or less, toavoid such oxidation.

Over time, the nanofiltration membrane will become clogged with everincreasing amounts of the higher molecular weight components that areremoved as the retentate. This is typically evidenced by a reduction inthe flow rate of the extract permeate. Also, as the membrane becomesclogged, its processing efficiency decreases. Accordingly, thenanofiltration membrane should be periodically cleaned or replaced tomaintain process efficiency and to ensure that undesired highermolecular weight components in the extract are removed to an adequatedegree.

E. Other Optional Steps

The treated, filtered green tea extract of the present invention can bedried to provide reconstitutable tea extract solids. Conventional dryingmethods, such as freeze drying, vacuum belt drying and spray drying canbe used to provide a substantially water-free, shelf stable powder whichcan be reconstituted. Preferably, the extract is concentrated byevaporation (thermal) under a vacuum. A concentrated extract suitablefor drying typically has from about 25 to about 60% soluble solids,preferably from about 30 to about 60% and most preferably from about 40to about 60% soluble solids. It is preferable during these concentrationand drying steps that the temperature of the extract not exceed about70° C., and most preferably not exceed about 50° C.

F. Characteristics of Treated and Filtered Green Tea Extract

The treated and filtered green tea extract obtained according to theprocess of the present invention has a number of unique characteristics.In particular, these extracts contain an enriched level of the desiredcatechins. The enriched level of catechins present in this green teaextract is measured according to the present invention by the level offour key catechins or their derivatives: epicatechin, epigallocatechin,epicatechingallate, and epigallocatechin gallate. Green tea extractsobtained according to the process of the present invention have, on a 1%soluble solids basis:

(1) at least about 130 ppm, preferably at least about 200 ppm, mostpreferably at least about 270 ppm, epicatechins;

(2) at least about 300 ppm, preferably at least about 450 ppm,preferably at least about 550 ppm, epigallocatechins;

(3) at least about 350 ppm, preferably at least about 500 ppm, mostpreferably at least about 850 ppm, epigallocatechingallates;

(4) at least about at least about 60 ppm, preferably at least about 100ppm, most preferably at least about 175 ppm, epicatechingallates;

The green tea extracts of the present invention are also enriched intheanine (5-N-ethyl-glutamine), a component found primarily in tea thatmodifies and mellows the astringency of the catechins. Green teaextracts obtained according to the process of the present invention haveat least about 50 ppm, preferably at least about 100 ppm, mostpreferably at least about 150 ppm, theanine.

The green tea extracts of the present invention that are notdecaffeinated are also preferably characterized by certain minimumlevels of caffeine. Green tea extracts obtained according to the processof the present invention typically have at least about 450 ppm,preferably at least about 600 ppm, most preferably at least about 700ppm, caffeine.

The green tea extracts of the present invention are also characterizedby certain maximum levels of metal ions. The level of calcium,magnesium, manganese, aluminum, zinc and iron components is used in thepresent invention as an indicator of how effectively the metal ions areremoved from the green tea extract during the cation exchange treatmentstep. Green tea extracts according to the present invention have about10 ppm or less, preferably about 5 ppm or less, each of calcium,magnesium, manganese, aluminum, zinc and iron components.

The green tea extracts of the present invention that are also preferablycharacterized by certain minimum levels of titratable acidity (TA). Whenthe green tea extract is treated with a strongly acidic cation exchangeresin, hydrogen ions are added that impart a smooth, less tart,astringent taste. Green tea extracts of the present invention preferablyhave a TA of at least about 0.1%, most preferably at least about 0.2%.

The green tea extracts of the present invention are also characterizedby improved clarity. The clarity of the extract is determined accordingto the present invention by measuring the absorbance of the extract at600 nm. Green tea extracts obtained according to the process of thepresent invention have an absorbance of about 0.06 or less, preferablyabout 0.04 or less, when measured at 600 nm.

The green tea extracts of the present invention are also preferablycharacterized by improved color. The color of the extract is determinedaccording to the present invention by measuring the absorbance of theextract at 430 nm. Absorbance values measured at 430 nm reflect thedegree of brownish color in the extract that can be caused by thepresence of thearubigins, theaflavin monogallate, theaflavin digallate,pectins, proteins, chlorophylls and their respective degradationproducts. Green tea extracts obtained according to the process of thepresent invention have an absorbance of about 0.6 or less, preferablyabout 0.4 or less, when measured at 430 nm, i.e., have less of abrownish color.

G. Beverages Using Treated and Filtered Green Tea Extract

The green tea extracts prepared according to the process of the presentinvention can be used in a variety of beverages. The green tea extractor the respective green tea solids derived from the extract are includedin the beverage in a flavorful amount What constitutes a “flavorfulamount” will depend on a variety of factors, including the flavoreffects desired, the type of beverage involved and like factors. Thebeverages of the present invention typically comprise from about 0.01 toabout 1.2%, preferably from about 0.05 to about 0.8%, green tea solids(including any other soluble solids present as a result of processing ofthe extract such as erythrobic, ascorbic and/or citric acid duringacidic extraction).

Besides green tea, the beverages of the present invention can comprisean effective amount of other flavor systems such as a fruit juice,vegetable juice, fruit flavors, vegetable flavor, as well as mixtures ofthese flavor components. In particular, the combination of green teatogether with fruit juices can have an appealing taste. The juice can bederived from apple, cranberry, pear, peach, plum, apricot, nectarine,grape, cherry, currant, raspberry, gooseberry, elderberry, blackberry,blueberry, strawberry, lemon, lime, mandarin, orange, grapefruit,cupuacu, potato, tomato, lettuce, celery, spinach, cabbage, watercress,dandelion, rhubarb, carrot, beet, cucumber, pineapple, coconut,pomegranate, kiwi, mango, papaya, banana, watermelon, tangerine andcantaloupe. Preferred juices are derived from apple, pear, lemon, lime,mandarin, grapefruit, cranberry, orange, strawberry, tangerine, grape,kiwi, pineapple, passion fruit, mango, guava, raspberry and cherry.Citrus juices, preferably grapefruit, orange, lemon, lime, and mandarinjuices, as well as juices derived from mango, apple, passion fruit andguava, as well as mixtures of these juices are most preferred.

The amount of these other flavor systems that is effective (i.e.,“effective amount”) in the beverages of the present invention dependsupon a number of factors, including the source(s) of the flavor system,the flavor effects desired and like factors. When fruit and/or vegetablejuices are included, the beverages of the present invention can comprisefrom about 0.1 to about 90%, preferably from about 3 to about 35%, andmore preferably from about 3 to about 10% juice. (As measured herein,the weight percentage of fruit juice is based on a single strength 2° to16° Brix fruit juice.) The fruit and/or vegetable juice can beincorporated into the beverage as a puree. comminute or as a singlestrength or concentrated juice. Especially preferred is theincorporation of the fruit juice as a concentrate with a solids content(primarily as sugar solids) of from about 20° to about 80° Brix.

The flavoring system according to the present invention can alsocomprise natural and/or artificial flavors, flavor oils, extracts,oleoresins, essential oils and the like, known in the art for use asflavorants in beverages. These flavors can be selected from fruitflavors, botanical flavors, vegetable flavors and mixtures thereof.Particularly preferred fruit flavors are the citrus flavors includingorange flavors, lemon flavors, lime flavors and grapefruit flavors.Besides citrus flavors, a variety of other fruit flavors can be usedsuch as apple flavors, grape flavors, cherry flavors, pineapple flavors,elderberry flavors, cupuacu flavors and the like. Particularly preferredbotanical flavors are hibiscus, marigold, rose hips, orange blossom,cammomile, elderberry blossom, malve, lemon grass and chrysanthemum.

For flavor systems other than juices, the flavor(s) are typicallyincorporated into the beverage as a flavor emulsions. The flavoremulsion typically comprises a blend of various flavors and can beemployed in the form of an emulsion, alcoholic extract, or can be spraydried. The flavor emulsion can also include clouding agents, with orwithout weighting agents, as described in U.S. Pat. No. 4,705,691(Kupper, et al), issued Nov. 10, 1987, which is incorporated byreference.

When flavor emulsions are used, the beverages of the present inventiontypically comprise from about 0.2 to about 5%, preferably from about 0.5to about 3%, most preferably from about 0.8 to about 2%, of theemulsion. Flavor emulsions are typically prepared by mixing flavoringoils (0.001 to 20%) with an emulsifying agent (1 to 30%) and water,along with clouding agents if an opaque beverage is desired. Flavoremulsions processed to provide emulsion droplet particles with diametersof from about 0.1 to about 3.0 microns are suitable. Preferably, theemulsion droplet particles are about 2.0 microns or less in diameter.Most preferably, the emulsion droplet particles are about 1.0 microns orless in diameter. The emulsifying agent coats the particularized flavoroil to aid in preventing coalescence and in maintaining an appropriatedispersion. Weighting agents (which can also act as clouding agents) canbe used to keep the emulsion droplets dispersed in the beverage.Examples of such weighting agents are brominated vegetable oils (BVO)and resin esters, in particular the ester gums. See L. F. Green,DEVELOPMENTS IN SOFT DRINKS TECHNOLOGY, Vol. 1 (Applied SciencePublishers Ltd. 1978) pages. 87-93, for a further description of the useof weighting and clouding agents in liquid beverages.

The beverages of the present invention can, and typically will, containan effective amount of one or more sweeteners, including carbohydratesweeteners and natural and/or artificial no/low calorie sweeteners. Theamount of the sweetener used (i.e., “effective amount”) in the beveragesof the present invention typically depends upon the particular sweetenerused and the sweetness intensity desired. For no/low calorie sweeteners,this amount varies depending upon the sweetness intensity of theparticular sweetener.

The beverages of the present invention can be sweetened with any of thecarbohydrate sweeteners, preferably mono- and or di-saccharide sugars.Sugar sweetened beverages will typically comprise from about 0.1 toabout 20%, most preferably from about 6 to about 14%, sugar. Thesesugars can be incorporated into the beverages in solid or liquid formbut are typically, and preferably, incorporated as a syrup, mostpreferably as a concentrated syrup such as high fructose corn syrup. Forpurposes of preparing beverages of the present invention, these sugarsweeteners can be provided to some extent by other components of thebeverage such as the fruit juice component, flavorants, and so forth.

Preferred sugar sweeteners for use in these beverages are sucrose,fructose, glucose, and mixtures thereof. Fructose can be obtained orprovided as liquid fructose, high fructose corn syrup, dry fructose orfructose syrup, but is preferably provided as high fructose corn syrup.High fructose corn syrup (HFCS) is commercially available as HFCS-42,HFCS-55 and HFCS-90, which comprise 42%, 55% and 90%, respectively, byweight of the sugar solids therein as fructose. Other naturallyoccurring sweeteners or their purified extracts, such as glycyrrhizin,the protein sweetener thaumatin, the juice of Luo Han Guo disclosed in,for example, U.S. Pat. No. 5,433,965 (Fischer et al), issued Jul. 18,1995 (herein incorporated by reference), and the like can also be usedin the beverages of the present invention.

Artificial no caloric or low calorie sweeteners that can be incorporatedinto the beverages of the present invention, alone, or in combinationwith carbohydrate sweeteners, include, for example, saccharin,cyclamates, acetosulfam, L-aspartyl-L-phenylanaine lower alkyl estersweeteners (e.g., aspartame), L-aspartyl-D-alanine amides disclosed inU.S. Pat. No. 4,411,925 (Brennan et al), L-aspartyl-D-serine amidesdisclosed in U.S. Pat. No. 4,399,163 (Brennan et al),L-aspartyl-L-1-hydroxymethyl-alkaneamide sweeteners disclosed in U.S.Pat. No. 4,338,346 (Brand), L-aspartyl-1-hydroxyethylalkaneamidesweeteners disclosed in U.S. Pat. No. 4,423,029 (Rizzi),L-aspartyl-D-phenylglycine ester and amide sweeteners disclosed inEuropean Patent Application 168,112 (Janusz), published Jan. 15, 1986,and the like. A particularly preferred low calorie sweetener isaspartame.

Beverages sweetened with aspartame have a characteristic aftertaste thatis unattractive to many. Surprisingly, this aspartame aftertaste issubstantially suppressed in beverages containing green tea extractsprepared according to the present invention. This surprising benefit isespecially noticeable in beverages where aspartame is the primary sourceof sweetness, e.g., mixtures of aspartame and a carbohydrate sweetenersuch as high fructose corn syrup, where the high fructose corn syrup ispresent at a level about half or less that typically required forimparting adequate sweetness intensity.

The beverages of the present invention can comprise other optionalbeverage ingredients, including preservatives (e.g., organic acids),colorants and so forth. These beverages can also be fortified with from0 to about 110% of the U.S. Recommended Daily Allowance (RDA) ofvitamins and minerals, provided that such vitamins and minerals do notsubstantially alter the desired properties of the beverage (e.g.,ambient display times), and that such vitamins and minerals arechemically and physically compatible with the other essential componentsof beverage. Especially preferred are vitamin A (e.g., vitamin Apalmitate), provitamins thereof (e.g., β-carotene), vitamin B1 (e.g.,thiamin HCl) and vitamin C (i.e., ascorbic acid), although it isunderstood that other vitamins and minerals can also be used.

Beverages according to the present invention typically contain fromabout 80 to about 90% water for carbohydrate sweetened beverages and upto about 99% water for diet type beverages, i.e., those at leastpartially sweetened with low and/or noncaloric sweeteners. Preferablythe water is deionized. Beverage concentrates according to the presentinvention formulated with carbohydrate sweeteners typically contain fromabout 25 to about 75%, preferably from about 40 to about 60% water. Ifdesired, the beverage water can be carbonated. Usually a beverage willbe considered to be carbonated if it comprises more than about 30%,preferably more than about 100% by volume of the beverage of solubilizedcarbon dioxide. Carbonated beverages according to the present inventioncomprise typically from 100 to 450%, preferably from 200 to 350%, carbondioxide by volume of the beverage. Carbonated beverages usually containvery low levels or no pulp. The carbonated beverage can then be placedin a container such as a HDPE bottle or other suitable container andsealed. See L. F. Green, DEVELOPMENTS IN SOFT DRINKS TECHNOLOGY, Vol. 1(Applied Science Publishers Ltd. 1978), pages. 102-107, for a furtherdescription of beverage making, in particular the process forcarbonation.

H. Analytical Methods

1. Catechins and Caffeine

The levels of the specific catechins and caffeine in the green teaextracts and green tea solids are determined according to the presentinvention by an HPLC based method, using UV absorbance for detection, asdescribed by S. Kuhr and U. H. Engelhardt, “Determination of Flavanols,Theogallin, Gallic Acid and Caffeine in Tea Using HPLC,” Z.Lebensm.-Unters.-Forsch., Vol. 192, (1991), pages 526-529.

2. Theanine

The levels of theanine in the green tea extracts and green tea solidsare determined according to the present invention by capillaryelectrophoresis using laser induced fluorescence detection, as describedin H. E. Schwartz, K. J. Ulfelder, F-T A. Chen and S. L. Pentoney, 1994.“The Utility of Laser-Induced Fluorescence Detection in Applications ofCapillary Electrophoresis,” J. Cap. Elec., Vol. 1, (1994) pages 36-54.

3. Metal Ions

The levels of each of the metal ions in the green tea extracts and greentea solids are determined according to the present invention byinductively coupled plasma (ICP) emission spectrometry, as described inR. L. Dahlquist and J. W. Knoll, “Inductively Coupled Plasma-AtomicEmission Spectrometry: Analysis of Biological Materials and Soils forMajor, Trace and Ultra-Trace Elements,” Appl. Spectrosc., Volume 32, No.1, (1978), pages 1-30.

4. Titratable Acidity

The titratable acidity of the green tea extracts and green tea solids isdetermined according to the present invention by back titration with a0.3125 N NaOH solution to a phenolphthalein endpoint, as described in S.Nagy and J. A. Attaway, CITRUS NUTRITION AND QUALITY (ACS SymmposiumSeries 143 1980), pages 295-98.

5. Absorbance

Absorbance values at 600 nm and 430 nm for the green tea extracts andgreen tea solids are determined according to the present invention byvisible spectrophotometry using a Beckman DU-9 spectrophotometer withdistilled water as the blank.

6. °Brix

°Brix values for the green tea extracts and green tea solids aredetermined according to the present invention by using an Abberefractometer.

7. Soluble Solids

The levels of soluble solids in the green tea extracts and green teasolids are determined according to the present invention by using aZeiss refractometer set at 29° C. and a calibration table based ondissolved solids.

EXAMPLES

The following examples illustrate green tea extracts made according tothe present invention.

Example 1

Ascorbic acid (90.7 g.) and citric acid (136.1 g.) are dissolved indeionized water (176 kg.) at a temperature of 46° C. Chinese green teafannings (4.54 kg.) are slurried in the solution until the leaves arefully wetted. The tea extract is withdrawn from the slurry using atubular filter while at the same time warm deionized water (46° C.) ispumped into the slurry at the same rate to maintain the liquid level inthe slurry. Extraction is continued until the °Brix of the extractleaving the slurry reaches about 1%. The combined extract has a pH of4.2 and weighs 102 kg, and has 1.72% soluble solids. The extract is thencooled to ambient temperature and is then passed through a packed column(0.22 ft³ column bed) of Dowex® HCR-W2, a strongly acidic cationexchange resin made by Dow Chemical of Midland, Mich., at the rate ofabout 0.4-0.6 gallons per minute. The extract treated with the resin hasa pH of 2.7 and has the same % soluble solids as the starting extract.This treated extract is then passed through a filtration cartridgecontaining an OSMO SP-12® nanofiltration membrane (made by Osmonics,Inc. of Minnetonka, Minn.) with concentrate (retentate) recycling. Thecellulose acetate polymer from which the membrane is made has a nominalmolecular weight cut off of 1000 Daltons (corresponding to a pore sizeof about 20 Angstroms). The pressure across the membrane is maintainedat 200 psi which results in a permeate flow rate of about 500 mL/min.The feed temperature to the filtration cartridge is maintained at42°-43° C. by means of a cooling water spray on the membrane housing.The resulting extract permeate is found to have: 1.12% soluble solids;378 ppm epicatechin, 800 ppm epigallocatechin, 1409 ppmepigallocatechingallate and 280 ppm epicatechingallate; 992 ppmcaffeine; 200 ppm theanine; 0.012 absorbance units at 600 ηm; 0.16absorbance units at 430 ηm; 2.5 ppm aluminum, 7.3 ppm calcium, 0.8 ppmiron, 4 ppm magnesium, 3 ppm manganese and <1 ppm zinc; 0.25% titratableacidity. The extract permeate is then cooled to about 10° C. beforeevaporation under vacuum to yield a tea concentrate.

Example 2

Erythorbic acid (510 g.) and citric acid (216 g.) are dissolved indeionized water (34.5 kg.) at a temperature of 125° F. (51.7° C.).Chinese green tea fannings (4.31 kg.) are slurried in the solution untilthe leaves are fully wetted. The tea extract is withdrawn from theslurry using a tubular filter while at the same time warm (125° F.,51.7° C.) deionized water is pumped into the slurry at the same rate tomaintain the liquid level in the slurry. Extraction is continued untilthe °Brix of the extract leaving the slurry reaches about 1%. Thecombined extract (185 kg.) has a pH of 3.8, and has 2.08% solublesolids. The extract is then cooled to ambient temperature and is thenpassed through a packed column (0.98 ft³ column bed) of Wofatit KPS®, astrongly acidic cation exchange resin (sulfonated copolymer ofpolystyrene and divinylbenzene) made by Bayer of Pittsburgh, Pa., at therate of about 0.4-0.6 gallons per minute. The extract treated with theresin has a pH of 2.5 and has the same % soluble solids as the startingextract. This treated extract is then passed through a filtrationcartridge containing an OSMO SP-12® nanofiltration membrane withconcentrate (retentate) recycling and using the same pressure and flowrate conditions as Example 1. The feed temperature to the filtrationcartridge is maintained at 100°-105° F. (37.8°-40.6° C.) by means of anon line heat exchanger. The resulting extract permeate is found to have:0.75% soluble solids; 223 ppm epicatechin, 503 ppm epigallocatechin, 670ppm epigallocatechingallate and 138 ppm epicatechingallate; 551 ppmcaffeine; 115 ppm theanine; 0.007 absorbance units at 600 ηm; 0.06absorbance units at 430 ηm; 5 ppm aluminum, 6 ppm calcium, 0.9 ppm iron,5 ppm magnesium, 2 ppm manganese and <1 ppm zinc; 0.17% titratableacidity. The permeate is then cooled to about 50° F. (10° C.) beforeevaporation under vacuum to yield a tea concentrate.

Example 3

Chinese green tea fannings (817 kg.) are slurried in softened well water(2,000 gallons) containing erythorbic acid (91 kg.) and citric acid (41kg.) at a temperature of 125° F., with stirring, until the extract °Brixreaches about 4.5 (75 minutes). The slurry is pumped into a filter whichseparates the extract (first extract) from the used tea leaves.Erythorbic acid (11.3 kg.) is dissolved in warm (125° F.) softened wellwater (2,000 gallons) to provide an acid solution used to flush theresidual tea leaf material retained in the filter until the resultingrinse has a °Brix of about 1.8.

The first extract is cooled to room temperature and is then passedthrough a packed column (18.5 ft³ column bed) of Dowex® HCR-W2 at therate of about 35-40 gallons per minute. The extract treated with theresin has a pH of about 2.8. This treated extract is then passed throughan OSMO 80B® nanofiltration unit equipped with 40, 16 cm diameter OSMOSP-12® membranes. The pressure across the membranes is maintained at 200psi which results in a permeate flow rate of about 15 gallons perminute. The feed temperature to the filtration unit is maintained at110°-115° F. (43.3°-46.1° C.) by means of an in line heat exchanger.This extract permeate is then cooled to about 40° F. (4.4° C.) beforeevaporation under vacuum to yield a green tea concentrate.

Example 4

A sugar sweetened beverage according to the present invention isformulated from the following ingredients:

50 Kg Batch Ingredient Amount (%) (g/50 kg Beverage) Potassium sorbate0.03    15 Potassium chloride 0.03    15 Sodium citrate 0.1     50 WhiteGrape Juice Concentrate 1.2    600 Xanthan Gum 0.10    50 High fructosecorn syrup-55 12.0   6,000 Ascorbic Acid 0.04    20 Flavor 0.2    100Red #40 Solution (0.3%/water) 0.20   100 Green tea concentrate (50Brix)* 0.5    250 Citric acid 0.14    70 Phosphoric acid (1 Molar) 0.02   10 R.O. water 85.44  42,720 Total 100.0      50,000 g *Preparedaccording to Examples 1, 2 or 3

Thirty-five kg of water is placed in a suitable container equipped witha high shear stirrer. The ingredients are slowly added in the order andamounts listed above with vigorous stirring. Each ingredient isdissolved before adding the next ingredient. Vigorous stirring with slowaddition into the vortex is especially important to dissolve the xanthanin the solution. The remaining water is used to rinse the containers.For refrigerated products, aliquots are dispensed into clean bottles,followed by capping and refrigeration until use. For shelf stableproducts, a HTST (High Temperature Short Time) hot fill method is usedto insure microbially stable beverages.

Example 5

A diet type beverage according to the present invention is formulatedfrom the following ingredients:

34.1 kg Batch Ingredient Amount (%) (grams) Potassium sorbate 0.035 11.9Potassium chloride 0.028 9.55 Sodium citrate 0.1 34.1 Aspartame 0.0413.6 Flavor 0.2 68.2 Caramel color 0.075 25.6 Green tea extract (50Brix)* 0.60 205 Citric acid 0.04 13.6 Phosphoric acid solution (1 Molar)0.21 71.6 Velcorin (dimethyl dicarbonate) 0.02 6.82 R.O. water 98.633,640 Carbon dioxide 3 volumes 3 volumes Total 100.0 34,100 grams*Prepared according to Examples 1, 2 or 3

Thirty kg of water is placed in a suitable container equipped with ahigh shear stirrer. The ingredients are slowly added in the order andamounts listed above with vigorous stirring. Each ingredient isdissolved before adding the next ingredient. The remaining water is usedto rinse the containers. The solution is poured into a Zahm & Nagel 10gallon Series 9000 carbonator. Three volumes of CO₂ are added. Thecarbonated beverage is bottle and capped. Two hundred ppm of Velcorin(dimethyl dicarbonate) is added via a freshly prepared solution of 1%Velcorin in water immediately before capping. The bottles are capped,inverted several times and stored inverted for several hours to insureexposure of the entire bottle to the Velcorin.

What is claimed is:
 1. A green tea extract, which comprises, on a 1%soluble solids basis: a. a mixture of catechins comprising: (1) at leastabout 130 ppm of epicatechins; (2) at least about 300 ppm ofepigallocatechins; (3) at least about 350 ppm ofepigallocatechingallates; (4) at least about 60 ppm ofepicatechingallates; b. at least about 50 ppm of theanine; c. about 10ppm or less each of calcium, magnesium, manganese, aluminum, zinc andiron ions; d. an absorbance of about 0.06 or less when measured at 600nm.
 2. The green tea extract of claim 1 further comprising caffeine andwherein said catechins have a molecular weight range corresponding tothe nominal molecular weight cut off range of a nanofiltration membrane.3. The extract of claim 1 which has at least about 450 ppm caffeine. 4.The extract of claim 3 which has at least about 600 ppm caffeine.
 5. Theextract of claim 4 which has at least about 700 ppm caffeine.
 6. Theextract of claim 1 which has a titratable acidity of at least about0.1%.
 7. The extract of claim 6 which has a titratable acidity of atleast about 0.2%.
 8. The extract of claim 1 which has an absorbance ofabout 0.6 or less when measured at 430 nm.
 9. The extract of claim 8which comprises: a. a mixture of catechins comprising: (1) at leastabout 200 ppm of epicatechins; (2) at least about 450 ppm ofepigallocatechins; (3) at least about 500 ppm ofepigallocatechingallates; (4) at least about 100 ppm ofepicatechingallates; b. at least about 100 ppm of theanine; c. about 5ppm or less each of calcium, magnesium, manganese, aluminum, zinc andiron ions; d. an absorbance of about 0.04 or less when measured at 600nm; e. an absorbance of 0.4 or less when measured at 430 nm.
 10. Theextract of claim 9 which comprises: a. a mixture of catechinscomprising: (1) at least about 270 ppm of epicatechins; (2) at leastabout 550 ppm of epigallocatechins; (3) at least about 850 ppm ofepigallocatechingallates; (4) at least about 175 ppm ofepicatechingallates; b. at least about 150 ppm of theanine.
 11. Thegreen tea extract of claim 1 further comprising a sufficient amountwater to form a beverage.
 12. The green tea extract of claim 11 whereinsaid sufficient amount water is supplied by fruit juice, vegetablejuice, or mixtures thereof.
 13. A beverage, which comprises flavorfulamount of green tea solids, said green tea solids comprising, on a 1%soluble solids basis: a. a mixture of catechins comprising: (1) at leastabout 130 ppm of epicatechins; (2) at least about 300 ppm ofepigallocatechins; (3) at least about 350 ppm ofepigallocatechingallates; (4) at least about 100 ppm ofepicatechingallates; b. at least about 60 ppm of theanine; c. about 10ppm or less each of calcium, magnesium, manganese, aluminum, zinc andiron ions; d. an absorbance of about 0.06 or less when measured at 600nm.
 14. The beverage of claim 13 which comprises from about 0.01 toabout 1.2% of said green tea solids.
 15. The beverage of claim 14 whichcomprises from about 0.05 to about 0.8% of said green tea solids. 16.The beverage of claim 13 which further comprises an effective amount ofanother flavor system and an effective amount of a sweetener.
 17. Thebeverage of claim 16 which comprises from about 3 to about 35% juiceselected from the group consisting of fruit juice, vegetable juice andmixtures thereof.
 18. The beverage of claim 16 wherein said sweetenercomprises sugar in an amount of from about 6 to about 14%.
 19. Thebeverage of claim 16 wherein said sweetener comprises aspartame.
 20. Thebeverage of claim 13 where said extract has at least about 450 ppmcaffeine.
 21. The beverage of claim 20 wherein said extract has at leastabout 600 ppm caffeine.
 22. The beverage of claim 21 wherein saidextract has at least about 700 ppm caffeine.
 23. The beverage of claim13 wherein said extract has a titratable acidity of at least about 0.1%.24. The beverage of claim 13 wherein said extract has an absorbance ofabout 0.6 or less when measured at 430 nm.
 25. The beverage of claim 13wherein said extract comprises, on a 1% solids basis: a. a mixture ofcatechins comprising: (1) at least about 200 ppm of epicatechins; (2) atleast about 450 ppm of epigallocatechins; (3) at least about 500 ppm ofepigallocatechingallates; (4) at least about 100 ppm ofepicatechingallates; b. at least about 100 ppm of theanine; c. about 5ppm or less each of calcium, magnesium, manganese, aluminum, zinc andiron ions; d. an absorbance of about 0.04 or less when measured at 600nm; e. an absorbance of 0.4 or less when measured at 430 nm.
 26. Thebeverage of claim 25 wherein said extract comprises, on a 1% solidsbasis: a. a mixture of catechins comprising: (1) at least about 270 ppmof epicatechins; (2) at least about 550 ppm of epigallocatechins; (3) atleast about 800 ppm of epigallocatcchingallates; (4) at least about 175ppm of epicatechingallates; b. at least about 150 ppm of theanine.